Ubus broken since upgrade to 0.57

[rradillen]

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You should only file an issue if you found a bug. Feature and enhancement requests should go in the Feature Requests section of our community forum:

Home Assistant release (hass --version):
0.61.1

Python release (python3 --version):

Component/platform:
ubus

Description of problem:
Ubus fails to work at all it throws an exception since v0.57

Expected:
Ubus not to throw an exception and work as with 0.56

Problem-relevant configuration.yaml entries and steps to reproduce:

device_tracker:
  - platform: ubus
    host: 192.168.2.238
    username: root
    password: <censored>
    track_new_devices: false 
    dhcp_software: dnsmasq

Configure ubus and start hass. Watch in log

Traceback (if applicable):

Traceback (most recent call last):
  File "/usr/lib/python3.5/asyncio/tasks.py", line 241, in _step
    result = coro.throw(exc)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/device_tracker/__init__.py", line 717, in async_device_tracker_scan
    host_name = yield from scanner.async_get_device_name(mac)
  File "/usr/lib/python3.5/asyncio/futures.py", line 380, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.5/asyncio/tasks.py", line 304, in _wakeup
    future.result()
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/concurrent/futures/thread.py", line 55, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/device_tracker/ubus.py", line 54, in decorator
    return func(self, *args, **kwargs)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/device_tracker/ubus.py", line 103, in get_device_name
    name = self.mac2name.get(mac.upper(), None)
AttributeError: 'NoneType' object has no attribute 'get'
2018-01-23 16:35:13 ERROR (MainThread) [homeassistant.core] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/lib/python3.5/asyncio/tasks.py", line 241, in _step
    result = coro.throw(exc)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/device_tracker/__init__.py", line 717, in async_device_tracker_scan
    host_name = yield from scanner.async_get_device_name(mac)
  File "/usr/lib/python3.5/asyncio/futures.py", line 380, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.5/asyncio/tasks.py", line 304, in _wakeup
    future.result()
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/concurrent/futures/thread.py", line 55, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/device_tracker/ubus.py", line 54, in decorator
    return func(self, *args, **kwargs)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/device_tracker/ubus.py", line 103, in get_device_name
    name = self.mac2name.get(mac.upper(), None)
AttributeError: 'NoneType' object has no attribute 'get'